This invention relates to testing devices and particularly to an audible resistance or voltage tester.
The prior art includes U.S. Pat. No. 3,689,832 to Leto et al which basically discloses a resistance tester for producing an audible tone that varies with the resistance up to approximately 25,000 ohms resistance. U.S. Pat. No. 3,284,707 which issued to Henry H. Clinton discloses a circuit continuity or resistance tester having audible output signals while Mason et al, U.S. Pat. No. 3,287,975 is directed to a temperature indicator having an audible signal. The aforementioned prior art patents are not intended to be an all-inclusive list of pertinent patents.
The present invention differs considerably from the prior art in circuit structure and capability. The Audi-Meter device of the present invention comprises a wide range resistance and a medium range voltage tester which may be packaged in a small rectangular box to fit into shirt pockets. The device, through the use of suitable probe, can also be used as an audio signal source. The tester further includes protective circuitry to prevent circuit damage during testing in an active circuit.